It is known that the manufacture of almond paste involves the preparation of a mother almond paste which is a product of the crushing of a certain quantity of blanched sweet almonds associated in particular with saccharose. The various crushing steps and the different treatments require that this mother paste contain a certain percentage of water.
The mother almond paste thus contains as its principal components almond and saccharose, and a certain percentage of water.
This product takes on the name of almond paste as soon as it has been dehydrated to a water content of about 10% by weight. It is in this step that the various elements are added which permit modification of its texture, taste, appearance, and even its shelf life.
Depending on the sugar content, which may vary from one-third to three-quarters of the total quantity, a secondary distinction may be made in the qualities of the almond pastes, which are identified either as almond pastes for confectionery or as almond pastes for pastry-making.
Generally, the usual composition of almond paste confectionery is the following:
Minimum content of almond oils: 17% PA1 Maximum content of sugar: 66% PA1 Maximum content of residual moisture:
for a content of almond oils of between 17% and 22%: 10% PA2 for a content of almond oils of between 22% and 28%: 12% PA2 for a content of almond oils higher than 28%: 17%
The almond oils derive from the incorporated almonds.
At the present time there are two manufacturing processes which may be distinguished, one being a combined process of cooking and crushing, and the other an evaporation-crushing process.
The first process, also termed the French process, comprises several independent and parallel steps.
First, dry blanched almonds are grated and then subjected to pre-crushing on a special cylinder crusher, for the purpose of tearing a large number of cells which enclose the almond oil, and thereby obtain pure almond paste.
The various sugars, saccharose, invert sugar and glucose syrup are jointly mixed with a certain quantity of water to produce a direct solution, while a cooking step enables the quantity of water to be reduced and the consistency of the paste required for the manufacture to be obtained.
Thus, the products issuing from the two preceding steps are introduced into a combined cooker and malaxator for malaxating, followed by cooling and crushing. It is in the course of this step that the various perfumes, alcohols and other additives, and the required quantity of invert sugar for obtaining the desired proportions, are added to the mixture to produce the almond paste.
The evaporation-grilling process, also termed the German process, is a discontinuous process, but contains all the steps in series.
The blanched white almonds are mixed with crystallized sugar and pre-crushed, and the mixture is then subjected to crushing. Thereafter, water is added to facilitate, during the grilling, Maillard reaction which thus develops the formation of the aromatic substances. Also, evaporation of a certain quantity of water occurs. Cooling is then necessary, and is generally achieved by a current of cold air, and the product thus obtained is termed the mother almond paste. Added to this mother paste are confectioner's sugar, glucose syrup and other additives which, when mixed, result in the almond paste.
The differences between these two processes of course result in variants in the rheological and organoleptic properties of the finished product. Indeed, the color and the taste may vary, since the Maillard reaction is not developed by the same steps nor in the presence of the same constituents.
Moreover, the aromatization or the addition of additives may be carried out more or less easily in either of the processes, and it is clear that there is no fundamental difference between the two processes, both being in series or in parallel, but discontinuous.
In the manufacture of some food products, processes and devices which are as "continuous" as possible have long been sought.
Thus, FR-A-2 257 235 discloses apparatus for treating or manufacturing food products, for example almond paste, whose purpose is to limit the many losses of time due to the necessity to pass from one apparatus to another.
This apparatus mainly comprises, with the vessel for treating the raw materials, two liquid-containing tanks one of which has a heating apparatus for bringing the liquid to the maximum termperature of utilization, whereas the other has a refrigerating apparatus for bringing the liquid to low temperature, and a circulating pump drawing in the liquid is provided for each tank.
There is also known, from FR-A 2 331 966, a process for preparing paste from seeds of stone-fruits, in which the fruit stones are sorted out, washed and shelled, optionally dried and ground with sugar and other ingredients by means of tools rotating very rapidly, after which this paste is grilled at a certain temperature, and finally cooled. During the crushing step itself, the product receives sufficient energy to ensure that the mixture is achieved in an intimate manner, the heating being effected by the direct injection of hot gas, preferably steam.